Determine the empirical formula for a compound that is found to contain 10.15 mg P and 34.85 mg Cl.

Question

Quizplus · Accepted Answer

To determine the empirical formula, we need to first convert the given masses of P and Cl to moles using their molar masses. 
Molar mass of P = 30.97 g/mol 
Molar mass of Cl = 35.45 g/mol

10.15 mg P = 0.000328 mol P 
34.85 mg Cl = 0.000981 mol Cl

Next, we need to determine the simplest whole-number ratio of P to Cl atoms. 
P:Cl = 0.000328/0.000981 ≈ 1:3

Therefore, the empirical formula is PCl3 which is closest to option E.

Determine the Empirical Formula for a Compound That Is Found